NREL Study: Eastern Interconnect Would Strain If 30% Of Annual Electricity Was Solar And Wind
A high fidelity simulation of the North American Eastern Interconnect known as ERGIS–Eastern Renewable Generation Integration Study–indicates that the system could continue to function in the year 2026, even if as much as 30% of its annual electricity generation and consumption was produced using variable power sources like the wind and the sun.
At the high end of the penetration levels studied, there are times when the wind and sun together provide as much as 52% of the total demand and as little as 10%. Sunrise and sunset routinely become periods of intense system response. On some days, 140 GW of production must shift from solar and wind to gas or coal fired generators during a period lasting less than six hours.
A press conference was held in late August to announce the release of a report that describes the creation and initial results from ERGIS.
During the press conference, Aaron Bloom, the ERGIS study project manager, stated that the project results summary describes four specific scenarios chosen with inputs from a Technical Review Committee. He also acknowledged that there were many more scenarios and constraining assumptions that would be of interest to decision makers. NREL expects and encourages requests from other research groups to use the tools developed during the project to explore a wide range of possibilities and answer questions that the initial team had not considered.
Genesis Of ERGIS
The Eastern Interconnect is the power industry’s name for the world’s largest, most complex and economically critical system. It is the electrical power grid that serves the geographic half of the US from eastern sections of Montana and New Mexico–excluding most of Texas–to the Atlantic coast plus the central and eastern provinces of Canada with the exception of Quebec.
That service territory is one of the world’s most densely populated and productive regions; virtually every activity in the region depends on the reliable flow of electricity from thousands of generating sources to hundreds of millions of customers. The system has been planned and constructed over the past century to handle an ever changing load and to be as resilient as economically feasible in the event of unplanned events like generator failures, transmission line faults and severe weather.
During the past decade there has been increasing momentum to provide electricity generated by capturing natural energy flows from the wind and sun. These generators reduce overall system fuel consumption and produce no CO2 when they are operating, but their output is almost completely dependent on variable weather conditions and the predictable rotation of the Earth.
The driving forces for added sources of weather dependent power and the need to study their operational impact were: efforts to reduce CO2 emissions from electricity production, “state renewable portfolio standards (RPS), federal policies affecting the tax structures of wind and PV projects, renewable technology advancements, and cost decreases” pg. 1
Starting in 2012, the National Renewable Energy Laboratory was tasked with building a high fidelity model of the system that could help decision makers understand the operational impacts for the system of a rapidly increasing share of electricity from weather-dependent sources.
The NREL team had access to the high performance computing capabilities of NREL’s Energy Systems Integration Facility, which includes a system called Peregrine. That massive array of processors and storage is considered to be one of the 50 fastest computers in the world and is the highest ranking one that is dedicated to studies of renewable energy and energy efficiency integration.
Even though the team was using one of the most powerful computer systems in the world, they quickly realized they needed to develop a number of innovative problem solving techniques to enable solution of complex, multi-input equations in 5-minute intervals for an entire year without requiring months of runtime per scenario. In addition to the computing optimization work, the team made a number of simplifying assumptions that have the potential for increasing the gap between simulation and reality.
Examples Of Important Assumptions
At the high end, the southeast US is assumed to be able to obtain 15% of its wind electricity from wind farms in the Southwest Power Pool while Florida is assumed to be able to install 1.5 kW/person of distributed solar capacity – 50% more than any other area in the study and 10% of the installed capacity in the state. The Virginia-Carolinas area was assumed to be able to obtain 80% of its wind from offshore installations.
Note: Exactly one offshore wind installation has been completed in the US. It is expected to be operational by the end of 2016. It has a total generating capacity of 30 MWe and it is off of the coast of Block Island, RI.
The study used summarized weather data from 2006 as an input for both electricity demand and production capability from the wind and sun. Researchers acknowledged that using a single year of weather data imposed a fidelity constraint by possibly overlooking severe weather events like lengthy heat waves or the Polar Vortex.
Coal plant retirement assumptions were based on announced plans, old age and low utilization rates. All nuclear plants operating in 2010 were assumed to continue operating with the exception of Crystal River, Kewaunee, Vermont Yankee and Oyster Creek. When not in a planned outage, remaining nuclear plants were assumed to be operated at their nameplate capacity and not be used to follow any loads.
All coal, nuclear and natural gas plant retirements were assumed to be replaced with new natural gas fired generation.
Coal and natural gas fired power plants were assumed to be adequately supplied by fuel at prices predicted by the Energy Information Agency 2014 Annual Energy Outlook for the year 2026. Pipeline constraints were not modeled.
The entire Eastern Interconnect was assumed to be controlled by a single mathematical model for commitments and dispatch. The reality is that there are numerous regions within the EI that have a limited ability–both physically and procedurally–to transfer power into other regions. The single formula assumption often resulted in the model deciding to move power over much longer distances than is usually the case.
Value And Limitations Of High Fidelity Modeling
Unlike the facile statements about a 100% renewable energy future by renewable energy advocates like the Solutions Project, the ERGIS report and the associated animations should help responsible policy makers understand that it is not easy to maintain grid reliability as variable power sources like the wind and the sun play a growing role. The system becomes increasingly dynamic and uses up some of its installed resilience to handle such expected events as sunset.
The study team was honest enough to provide various forms of the following warning to policy makers in all three of the study’s main communications products–the final report, the executive summary and the press release announcing the availability of the study.
However, we did not investigate whether transmission and generation operators will have sufficient incentives to provide the necessary ramping, energy, and capacity services for futures like the ones we studied. While ERGIS shows it is technically possible to balance periods of instantaneous VG [variable generation] penetrations that exceed 50% for the EI, the ability of the real system to realize these futures may depend more on regulatory policy, market design, and operating procedures.
They did not note, however, that there weren’t any members of the technical review committee (TRC) who could help the researchers quantify the scale of “sufficient incentives” that might be required. The 20 member TRC included two professional renewable energy industry lobbyists–one from the American Wind Energy Association and one from the Solar Energy Industry Association–neither of whom has a documented technical or operational background.
People who will end up footing the bills and potentially suffering the consequences if the reduced resilience results in power limitations or outages should demand to know more about the required “sufficient incentives.” The entities who are assumed to provide the needed services will expect to be paid, sometimes quite handsomely. When read carefully, the ERGIS shows that increasing renewable penetration, even if the cost of the power generators themselves falls a bit, isn’t going to be easy, cheap or without risk to reliability.
The above was initially published on Forbes.com with the same title. It is reprinted here with permission. An abbreviated version has been used to stimulate a conversation on OurEnergyPolicy.org.
Rod Excellent article, what you do so well.
An excellent description of the problems involved in the distribution of power is explained in this book – https://www.nap.edu/read/21919/chapter/1 – which can be downloaded as a “guest.” There is also a good analysis of what is needed for the integration of renewables.
As described in – http://scitation.aip.org/content/aip/magazine/physicstoday/news/10.1063/PT.5.5020
“Power in an electric network does not travel along a set path, as coal does, for example. When utility A agrees to send electricity to utility B, utility A increases the amount of power generated while utility B decreases production or has an increased demand. The power then flows from the “source” (A) to the “sink” (B) along all the paths that can connect them. This means that changes in generation and transmission at any point in the system will change loads on generators and transmission lines at every other point—often in ways not anticipated or easily controlled (see figure 2).” Of the above link
And like moving water from one place to another takes power it also takes power to move electricity from one place to another. Today’s heavy use of computers and computer devices means that even millisecond outages are costly. Power distribution schemes use parallel feeds to minimise this. That results in power going around in loops doing nothing but heating the ground and air and wasting more power.
The study compared 2010 numbers to four 2026 case scenarios varying from 3% to 30% VRE penetration. A review of the macro capacity and generation numbers indicate that the dispatchable & base load thermal capacity remained the same across all scenarios (Table 17). I take this to mean that wind & solar only reduce generation, they don’t take fossil plants offline.
An additional 800 TWh of coal and gas generation (approx 50/50 split) are reduced when comparing the 3% to the 30% VRE scenario (figures 42 & 43). CO2 emissions are also reduced by an additional 33% in the 30% scenario (figure 92).
Instead of adding 250-300 GW of combined solar (0.16 CF) & wind (0.40 CF) capacity to generate 960 TWh of power (Table 26), what does adding 120 GW of nuclear look like in comparison? I assume this was modeled during the original planned nuclear build out in the the 70s or 80s.
I am confused by the “wind and solar won’t work all the time” argument that is used to justify the term “unreliables”. I would ask, “so what”? If it works 10%, 20%, 30% or 50% of the time, thats not a plus for the environment? And, as is currently being demonstrated by Costa Rica’s success of weaning themselves off fossil fuels for large blocks of time, through use of hydro, solar, and wind, does the term “unreliable” apply there too? This article is a bit perplexing to me, because I can’t figure out a real downside about renewables that the article outlines. It seems to me that the outlook for solar and wind can only improve as the technologies evolve, so wheres the beef in this article that one could perceive as being an article justifying the term “unreliable”? Wouldn’t “intermittent” be a more apropos term? The term “unreliable” brings to mind sudden outages, and contingencies that cannot be planned. But the term “intermittent” brings to mind a realized periodic shortfall that can be planned for and mitigated through the use of back up technologies and fuels.
“Costa Rica gets most of its electricity from hydroelectric plants and a recent period of unusually heavy rain allowed the country to reach the milestone. This clean power [hydro] is bolstered by geothermic energy from the country’s volcanoes and a small amount of wind and solar power. Most years, these sources allow Costa Rica to generate approximately 90% of its electricity without burning fossil fuels.”
More info at – https://www.theguardian.com/commentisfree/2015/mar/30/truth-behind-costa-rica-renewable-energy-reservoirs-climate-change
Do you consider the weather to be reliable? Can you control the speed of the wind?
Rod….Of course I don’t consider the wind reliable. But nor do I consider that it has to be reliable in order to contribute to the grid in a positive manner.
EP…..I’d prefer not to exchange comments with you. Its not that I don’t have a response, its that I’d prefer not to offer one. I don’t respect you, and your opinion, and knowledge, means nothing to me. As I’m sure you feel the same about me, can we just agree to ignore each other? Regardless of whether or not you are amiable to such an agreement, I can assure you thats what I intend to do. So, if you wanna waste your time spitting in my direction, its on you.
Btw Rod, if you reread the vomment of mine that you were responding to, you should be able to discern that I had already answered your question about unreliability. In fact I’m suprised at your question, and more than a little perplexed about your motive for asking it. Seems to me you just pretty much ignored what I was saying.
“vomment”…. what a delightful Freudian slip.
I will stop mocking and trolling you just as soon as you cease trying to bait and disrupt this forum. Given your inherent tendencies, that will be about the time that death or disability ends your posting career.
I don’t always respond to the full contents of a comment. Yours began with a direct challenge to my rebranding the sun and wind as “unreliables” instead of using the warm and fuzzy “renewables” that the marketers have chosen.
I consider both to be disruptive of the grid, making the job of maintaining a rock solid 60 Hz steady voltage, efficient power factor condition far more challenging that it needs to be. Sure, they can reduce fuel consumption a bit, but they do not alleviate the need to have sufficient controllable capacity to service the entire load because there is always a substantially larger than zero chance of having both no wind and no sun over a very large area.
Both energy sources have their uses, but grid connected power isn’t their forte. Historically, the push for them began during the early 1970s “energy crises.” It was initially a tactic to discourage people from logically turning to a massively scaled up nuclear program as a result of the proven economic and security risks of imported oil, strike plagued coal, and occasionally unavailable natural gas in the dead of winter.
The French were led by some independent thinkers who recognized the ploy for what it was.
Ploy or not, nuclear has done such a dismal job of marketing itself to the public at large, that it is gasping to survive. So, when you disparage the evolving energy sources of wind and solar, nuclear is not going to be the beneficiary, fossil fuel will be, particularly NG, and the fossil fuel industry’s “at any cost” methods of extracting it. This is particularly true if this electoral cycle produces the disaster I fear it might. Clinton will ignore muclear to pander to her base, and Trump will do so to line the pockets of himself and those powerful in the fossil fuel industry. Can remaining NE energy plants, here in the US, survive four or eight years of an unsympathetic political machine working in favor of fossil fuel, or renewables? Doubtful. Theres a train rushing by, and if you don’t jump on board, you will be chasing the caboose. And its moving faster than you’ve shown us you can run.
Frankly, I think the NE crowd is contributing to their own demise. You need partners, not enemies. Yet you, (generally speaking), seem hell bent to turn potential partners into enemies. This thread, obviously, is turning into a prime example, on a small scale, of what I’m talking about.
Another day in Tehachapi. Drove into town, and was greeted, once again, as usual, with the visual of hundreds of spinning wind turbines on the hillsides and hilltops east of town. Really, the days lacking a breeze here are more unreliable than the days where we experience a breeze sufficient to spin the blades. I’ve devoted some thought to this “unreliable” business in the last couple of days, since my last post, above. And the more I think about it, the more I think NE advocates are making a huge mistake using such rhetoric. I would assume that someone that studies weather, and compiles statistical data about weather patterns in specific areas, can predict with some accuracy the percentage of days that a specified area will experience wind in a year’s period. So it could be said that a specific area will have a reliable percentage of time during the year that a wind farm will produce energy for the grid. It is more than semantics. I don’t understand why you do not try to piggy back wind and solar with nuclear. You take an energy source, that John Q percieves as “clean”, and instead of using and building upon the clean marketing message that wind and solar have already established, you malign these energy sources, putting the ball back into the hands of the fossil fuel folks. Why can’t you sell NE as a partner to wind and solar? A complete package, working in tandem, as partners, for reliable energy and a clean environment? Frankly, your messaging sucks. And if you don’t think so, how’s what you are doing working out for you?
NREL has been working on that. Though dated, this NREL Study may give you some insight as to some of the problems.
FERC reliability requirements after the two east coast massive outages were more of a bandage than a solution.
To “average” out wind/solar fluctuations will take a massive investment ($Trillions) involving much more than a Smart Grid. Look at any of the typical storms that progress from the west coast to the east coast and the areas covered by storms. That means no Wind power, no Solar power over several states. To “average” that out requires moving power from where it is to where it isn’t. That means additional transmission lines involving almost a doubling of the existing number of HV transmission lines. Although the wind may be blowing all large industrial wind turbines cut out at high wind speed. They stay cut out till the wind speed has dropped back to acceptable level for a specific period of time. This is so that they do not short cycle (come on then quickly shut down) which would cause even more problems. Thus, High wind does not mean more power it means no power (as discussed in the referenced report.)
You will also note in the graph that there is a loss of about 40 MW within minutes due to the whole wind farm shutting down due to high wind speed. I have been in the Control Room when a different power plant went off line unexpectedly. As a result we were given an increase in load of over 50 MW. This rapid increase in load was interpreted as a fault on the grid causing breakers controlled by the grid operators, not in the plant substation, to open to protect the grid. It was all we could do to keep the plant on line. Another benefit of the NRC mandated elimination of the ability of the NPP to automatically cope with off-site loss of power events. A result of bureaucrats that have never operated a plant making rules. Sort of like the rule change that NTSB is forcing on big-rigs of making governors that limit speed to the posted speed limit based upon GPS/highway location.
Rich…thanks for your informative and civil reply.
Because those pushing “renewables” have already decided that natural gas is going to be the partner. Because they are NG interests. How many times do we have to tell you this before you believe it?
You can see the blades spinning, but you cannot see how much power they’re putting on the grid. Can you distinguish barely operational from maximum output? Do you think it doesn’t matter? Try to understand the significance of what you can’t see directly.
It’s not rhetoric, it’s dialectic. It’s 100% true to fact. But as in so many other areas, this does not prevent ideological or economic enemies from flatly denying it. “A lie travels halfway around the world before the truth has its boots on.”
We keep trying to get you to think about those gaps: what produces the energy when wind is NOT there? For the sake of the earth, what can we allow that energy to be produced from? The answer is “nothing that contains fossil carbon”.
Consider the daily demand curve. There is a minimum in the 2-5 AM region. Why shouldn’t everything below that demand minimum be served by emissions-free nuclear power, without un-needed “partners” which rely on fossil backups? Solar is dead then, and wind is easily curtailed. Why shouldn’t wind be next to last in grid priority, instead of first because it’s “renewable”? Why should we pay wind farms a PTC to make power we do not need, or which pushes more reliable emissions-free sources off the grid and increases net emissions? Do you not believe that this is literally an EXISTENTIAL crisis for humanity?!
You never stop to consider that the perception might be wrong, manufactured by people who have more interest in immediate profits than long-term survival.
That blindness will be humanity’s undoing.
@poa and E-P
You can see the blades spinning, but you cannot see how much power they’re putting on the grid.
This is a key point worth quantifying. As a sailor, I had some understanding of the power of the wind, but the limitations of sailboats obscured the magnitude of the variations. There isn’t much difference in boat speed between a day with a comfortable breeze of 10 knots and a howler with 25-30 knots.
However, the POWER generated by that change in velocity is dramatically different because it is a function of the velocity cubed. If wind speed merely doubles, the power increases by a factor of 8. If it triples, it increases by a factor of 27.
That is impossible to see, because a wind turbine generator won’t visibly spin any faster. It simply grenerates more power and more current. They are designed to maintain a constant speed by varying the excitation of the generator just like all other turbine generators.
Yeah buts….well, they don’t work all rhe time…….well, they may be spinning, but that doesn’t mean they are producing power…..why do we need them when we have an energy source that can operate without them?
Hows that attitude working out for you guys? Enjoying great success? Gee, whats that I just heard? Another NE plant’s doors slamming shut?
Suicide is such an ugly thing to watch.
For the gazzilionth time, I don’t speak for the nuclear industry. I don’t accept any responsibility for its current troubles since few, if any, of my many recommendations and comments have influenced decisions.
I’m not interested in allying with unreliables. They’re marketing expensive, limited energy that would not exist without continuing taxpayer support.
Nuclear fission is superior to hydrocarbon combustion. If its discovery had not coincided with a world war that gave the government an excuse to seize early control, it would have been developed into a dominant power source decades ago.
We don’t. There’s been 4 decades of propaganda that we need to run on “renewables”, defined as wind and solar, but with 4 billion tons of uranium in the oceans and 32,000 added every year while human energy consumption needs just 5000, nuclear is just as renewable and far more sustainable than the so-called “renewables”
If you were listening carefully you heard the Energiewende being rolled back, the so-called “denuclearization” of France being quietly dropped, New York moving to save its nuclear capacity, Illinois on the verge and even a grassroots movement in California to save its surviving nukes. There’s even a movement to re-commission San Onofre. This was unthinkable 5 years ago. The truth is finally getting past the fog of decades of lies.
Lliving at the epicenter of the national insanity over nuclear power probably makes it difficult for you to see anything else.
If you cannot understand what a man put into writing 150 years ago and has since been confirmed millions of times by experience, the fault is yours.
“Hows that attitude working out for you guys? Enjoying great success? Gee, whats that I just heard? Another NE plant’s doors slamming shut?
Suicide is such an ugly thing to watch.”
There’s the other thing that is going on. In terms of a package deal, who do you want as your business partner, somebody who just barely makes it financially or somebody who brings both the cash in and brings more business in? Right now – Natural gas is a good partner. Sure he puts out a little messy carbon. But, it is all dispersed in the air.
As you drive by a gas turbine, it presents a clean neat appearance. Not much of a plume, no big coal piles, no mile long trains and no fly ash. Beats coal plants. He doesn’t have big ugly rocks and razor wire like a nuke plant. His needs are little in terms of maintenance and daily staff.
Nuke is a tough partner. One small mistake on his part and the law will shut him down. The law is more than on his doorstep. The law is in his house. His mistakes can cost you big money to fix.
Combining nuke and wind could be a tough sale with little to no commission.
Sharks gotta swim, windmills gotta spin. Trite, but a kernel of truth. Sharks — the larger ones anyway — cannot pump enough oxygen-bearing water through their gills to sustain life. They need net motion to aid the flow. They swim or they drown.
Windmills are totally different, but you still won’t see many idle, even on a dead calm day. Because their lightweight composite airfoil blades are so massive their hub bearings will birl and pit under their weight, if not kept moving.
So keep ’em moving. Slowly, but moving. The generator in a wind-turbine’s hub is a motor-generator just like any other DC generator. And its parasitic power drain on a calm day is reasonably inconsequential compared to the power that turbine can produce when you [i]don’t[/i] need it.
But your earlier question r.e. “Why the perceived antipathy towards building out wind+sun [i]now[/i]? Collect what carbon savings we can, and worry about the other 70% later” is good and the answers go somewhat beyond the “because they’re an expensive distraction and we don’t need them.”
I’ve been collecting material for an article I don’t anticipate finishing any time soon. The Duck Pond is a marketing blurb from turbines division at Siemens Energy. Their job is to sell gas turbines that will match fluctuating load with minimum emissions.
Siemens does a good job, but makes no claims about it being good enough. Just satisfy the RPS and keep the lights on. I like solar Duck Pond curves cuz they’re easy to visualize. Easy to visualize when the sun shines, and when it does not. Wind is a bit harder as it blows (on average) a bit more at night, and whenever during the day. Harder, but still only a short step after one gets a grip on sun.
We can’t post images here — Rod no doubt has moderation reasons — but refer to figures 2, 4 and 10 of the linked article, and what they mean when wind+sun market penetration reach their nominal capacity factor of about 30% (ymmv but not by much). At this point — beyond year 2020 pictured but within the 2035 time frame envisioned by California — the belly of the duck in figures 2 and 4 sags down not just to 12 GW, but absent massive storage of energy too cheap to matter (another article) — scrapes bare farmer’s dirt at 0. And that daily operation of Seimens’ SCC5-8000H flex-cycle turbine has no 100 MW of baseload: it becomes all flex-dispatch and none of Miss Bonnie’s feel-good fuzzies will keep it operating anywhere near 60% thermal — more like the 30% she gets from her peaker plants because that’s effectively what it becomes.
But that’s okay: she’ll meet both load and the RPS, and everyone gets paid.
And climate change? Remember climate change? This song is about climate change. But it seems to have been lost in the din.
At 30% wind+sun and 70% gas where all gas efficiency was 30% peaker, your per MWh emissions would actually increase 40% over if all generation were provided by fully combined-cycle gas at 60% thermal.
Now I seriously doubt it will be that bad: all generation will never be provided by fully combined cycle at 60% thermal, and even at 30% wind+sun full-belly duck there will be sufficient predictability to drag much of the gas efficiency up out of the cellar. There will be some net emissions reduction over 100% gas generation alone.
But “some” is not the same as “a lot”. We’ve burnt a lot of money and real estate making comparatively little progress, and we’re still talking ghg-emitting gas. We’re still burning far too much fracked gas and still emitting far too much greenhouse gas to have more than a few decades effect on climate change. In the process we’ve utterly destroyed the dispatchable base-load generation market and promised it all to unreliable generation + polluting gas.
“Cross that bridge when we come to it! By then energy storage will be too cheap to matter!! Look at the trends!!! And we’ll need new transmission anyway!!!!”
And someone else will pay for it. Here. We’ve set up our subsidy and RPS regimes specifically to keep that part off the books.
The Rest of the World might not be so lucky.
(Don’t take it personally: you asked a good question.)
Link: The Duck Pond.
Ed Leaver Excellent discussion from which I learned a lot about the practicalities about dispatching electricity that I did not know before. I think it is interesting that NREL did another study a few years ago involving coordination by seven Western States. Even with perfect cooperation, which is a tall order given the rugged independence of the American West, the maximum penetration of solar and wind, before grid instability became unmanageable, was again 30%. Unless one has access to some really cheap method for the effective storage of electricity, such as existing hydroelectric dams, no country or district has ever managed to run a modern economy using just solar and wind. Batteries are not a likely solution unless one either carries out an unprecedented level of recycling of the raw materials need to make a battery (e.g., lithium carbonate), or one develops completely different approaches where discarding large amounts of environmentally questionable materials (e.g., zinc) becomes acceptable practice.
The proven approach to successful technologies has always been to conduct small-scale experiments to demonstrate scientific feasibility before large-scale deployment. For a complex set of reasons that visitors to Atomic Insights struggle to understand, governments everywhere have made an exception for solar and wind, while placing onerous restrictions on the one technology that could provide realistic amounts of clean back-up for these flawed technologies: nuclear power.
I have just one small quibble with your post. You state that “wind blows a bit harder at night” than during the day. My impression for onshore wind is that it blows mostly at night for a sound reason: cold air descends and warm air rises. At night as the ground cools, the air descends, meets the obstruction provided by a solid surface, on which wind turbines rest, spreads horizontally and provides the motive force that turns the turbines. Rising air during the day does less good because the wind speeds are not high at the level of the blades. And really hot spells in the summer can result in no useful wind for weeks at a time.
The claim by enthusiasts that solar and wind are complementary is thus nonsensical, because strong wind at night and in winter does not help solar during the summer and day when sunlight is strongest and present (if no intervening clouds or fog get in the way). These factors work against relying on gusts of wind, which is not just intermittent, but unpredictable at a fundamental level, because convective motions in the troposphere is a turbulent phenomenon that led to the earliest scientific example of what it means to be chaotic. The ocean plays a moderating influence on weather, so off-shore wind turbines are more reliable than on-shore ones, but they are also a lot more expensive.
The renewables scenarios ARE mostly nonsense, but most people don’t have the technical chops to tell that inside the prettily gift-wrapped box there is nothing but junk.
Worse, the people who do, do not have the sophisticated and well-financed PR apparatus to make their case to the public.
Can I get you to contact me off-line (mail link is at The Ergosphere blog)? I’ve got some questions regarding biochar production byproducts which might kick off something fruitful.
Engineer-Poet I prefer not to give my email address to people that I meet on public forums. Non-proprietary discussion is possible in the public arena, but nasty disputes may arise in scientific collaborations when the parties do not know each other well. I have a coterie of collaborators with whom I already work, and it would be unfair to them if I were not to show discretion in this matter. Sorry to be unable to take up your kind offer on this issue.
Whatever, I have no expectations of confidentiality, I just didn’t want to throw a bunch of stuff here that was OT for the forum. Since you want it public, here goes.
I wondered if you had done any analysis of the quantity, composition and heating value of the off-gas of the STP process, and if there was any progress from batch handling to a continuous-flow process. If the off-gas is of sufficient quality to power a gas turbine, you might have a way to close the loop on the energy inputs (turbine exhaust heat provides process heat for the STP step) and generate electric power as a byproduct. If you operate the process mostly during peak-demand hours you could collect carbon credits and peak wholesale electric prices at the same time.
If the off-gas has excess energy beyond what is required to drive STP, perhaps other valuable products could be collected from off-gas condensate. That’s one for the chemists.
I’ve seen enough designs for gasogenes built to run on charcoal that I’m certain that the entire STP plant could be powered by biomass, it just depends how much of the char product has to be diverted to process energy. The gasogene designs go back to WWI and earlier and there’s no IP involved.
Engineer-Poet Very intelligent points. We have measured the quantity and chemical composition of the off-gas from STR. When the process is carried out at 450 to 550 Celsius, it is essentially syngas: H2, CO, CH4, CO2, H2O. The H2O is easily condensed out of the mix, and one is left with gas that is potentially useful as an on-site fuel or, even more valuable, as a chemical synthesis feed stock.
For example, membrane separation of H2, CO, CH4, and CO2 would allow us to meet DOE’s target price of $1.40/kg for H2 because the operations are profitable even if we were simply to flare the gas. However, storage of the syngas at many of the remote sites where we hope the equipment will be used (e.g., high fire hazard zones containing beetle-killed pine trees) is not practical. Thus, this exciting application — synthetically replacing fossil fuels from the carbon and hydrogen produced by STR of biomass — is not on our immediate radar screen for protoype development.
We have also looked into burning the syngas for on-site electricity generation. As you say, such engines have been around since WW1. In an effort to make coal burning cleaner, China produces a lot of syngas by the coal-to-gas technology. They sell large cylinder engines that, with periodic cleaning, can handle the tars that remain in the gas. Because tars, as well as the acids produced by other pyrolysis approaches, are destroyed by STR in the salt, our very pure syngas could easily be used in the reasonably priced Chinese engines (which are coupled to alternators built by Siemens). However, even the smallest engine/alternator is too large to be transportable by truck, which is our criterion for the prototype.
Thus, our plan is to oxidize the syngas as additional heat for the salt, which also automatically oxidizes the charcoal fines that leak out of the porous basket. We call such a device a charcoal fines oxizer (CFO) and have a working prototype in our pilot plant in Taiwan. By FY 2020, we hope to have a supercritical CO2 (sCO2) system coupled to the STR/CFO, where existing turbines off-the-shelf (made by General Electric and other companies) with 10 MWe of capacity can be held literally in your hands.
Making biochar is a quasi-batch process performed by conveyor belt that moves porous baskets holding coarsely chipped wood or other forms of biomass (e.g., banana peels mixed with orange rinds
mixed with yard waste, etc.). Once one has piles of biochar, if one wants electricity instead of a soil amendment, one can pulverize the char and blow it into furnaces for generating steam and electricity. Better yet, use a STR/CFO coupled to a sCO2 Brayton cycle system to produce dispatchable electricity for the site and surrounding communities, with equipment transportable to any place that has waste biomass (pretty much anywhere people live).
Do you have any papers giving the quantities and ratios? This is the kind of thing I use as blogfodder.
There are commercial methanol synthesis plants set up to run directly on H2 and CO or CO2. If the syngas stream is sufficiently clean, you could produce a liquid fuel with considerable commercial value.
You might try looking at Capstone turbines; there are options as small as 30 kilowatts. The exhaust temperature is too low for your purposes but I’m sure that regenerator efficiency can be reduced until the EGT is as high as you want it to be. Another option is to use larger, heavier but more efficient and leak-free printed-circuit heat exchangers in lieu of the rotating mesh regenerator that Capstone appears to use to reduce weight and bulk. Doubling the weight of a 30 kW unit from its sub-600-kg baseline does not look too troublesome at first blush.
How tolerant is the system of typical contaminants of municipal solid waste, such as PVC and silicones? If that means corrosion or coating all the hot-section components with a thickening layer of glass over time, t’would be troublesome.
Heartening seeing biomass energy discussed as a positive option. I was once taken to task here for my advocation of biomass produced energy. One person actually opined that the almond and walnut growers, when retiring a grove, should allow the thousands of trees to decay naturally, rather than be fed to a biomass plant. Somehow, fallow farmland just doesn’t strike me as a wise alternative to biomass produced energy.
Although a good part of your contribution here is way above my level of knowledge, your comments have been extremely interesting and informative to me. I am curious about your opinion concerning the future of the so called renewables, and whether or not you see these energy technologies as having the capacity to evolve into viable and positive additions to our energy grid, or regarding the energy needs of single households. I realize that energy storage is a huge component of the equation. But to this layman, that regularly uses battery operated tools in plying his trade, I am truly astounded by the rapid evolution of the batteries used to power such tools. Surely this evolution of energy storage technology will continue, will it not?
poa Yes, I do think renewables can make a positive contribution to the battle against climate change. I especially like rooftop solar because it is the only energy technology that can be used naturally at a household scale, and therefore give individuals and their families a personal sensitivity of the importance to address the challenges of climate change. Plans to build solar panels into the construction of a roof so that it becomes an aesthetically pleasing piece of architecture is an especially attractive development.
However, residential rooftop solar primarily targets the well-to-do who have their own houses and can afford paying a premium for renewable electricity. It should not be subsidized at the expense of the less-well-to-do paying higher electricity rates because of the extra expense needed for grid stability created by wealthy owners of solar panels wanting to have two-way access to the grid. This access creates neither social justice nor climate justice.
Many advocates of renewables believe batteries are the answer for people to get off the grid. The Lazard organization performed a study in 2015 of the added cost of using batteries to store electricity from solar panels. Without considering local taxes, which vary from state to state, the unsubsidized cost of providing community-scale electricity by solar panels is US$107/MWh. Including storage by various existing battery technologies brings the total to:
Lithium Ion: US$430/MWh
which should be compared to
Natural gas combined cycle: US$65/MWh
Conventional biomass: US$74/MWh
Unless there is a revolutionary breakthrough in battery technology, it is a falsehood to claim that solar photovoltaics is already competitive with conventional means of generating and using electricity in a reliable manner.
For wind to become a reliable resource, based on the cheapest form of battery storage currently available (zinc), would require at least an extra US$246/MWh, which consists of $US134 for the capital equipment cost, US$18 for operations and maintenance (yes, large banks of batteries need maintenance), and US$74 for charge/discharge cycles (yes, batteries wear out when you charge and discharge them). In fact, the last item is the Achilles heel of battery storage, because they usually cannot hold more than a day’s worth of electric usage, and wind can be idle for weeks at a time. One can, of course, buy enough batteries to supply back-up for weeks, not days, but then multiply the above cost by the ratio of a week to a day.
Some fans of wind power (I am not among them because of their large intrusive footprints on land use) rely on technology to achieve a breakthrough in battery storage. Batteries have been around for centuries. Is it reasonable to suppose a revolutionary breakthrough for them is more likely than new generations of nuclear reactors being much better than those from fifty years ago?
Serious studies like the NREL one under discussion discount the likelihood of such breakthroughs in battery technlogy, and consider what’s possible with smart and coordinated grid management. Even accepting their optimistic assumptions, the maximum penetration for solar and wind is 30%. Moreover, no country that gone to such build-out levels have seen their carbon emissions actually go down — not Spain, not Denmark, not Germany. Apart for a fondness for renewables, what do they have in common? They don’t like, or they don’t have, much, hydropower and nuclear power plants.
So, yes, I think renewable have a role to play in the fight against climate change. But their adherents should recruit nuclear power and biomass as allies, not drive them away as an enemies.
Thanks for your response. Its prompts another question. You state…
“So, yes, I think renewable have a role to play in the fight against climate change. But their adherents should recruit nuclear power and biomass as allies, not drive them away as an enemies.”
I’m curious if you think that nuclear adherents should practice the same kind of wisdom, and seek to ally themselves with the renewable adherents, instead of, as you mention, driving them away as enemies?
Yes, making peace is a two-way street. So is making war.
Sadly, it only takes one to make war. If the attacked does not fight back, they are called “the loser”.
Engineer-Poet To start a war takes only one. To fight a war takes at least two. To put a peaceful end to war also takes at least two.
Let me give an example. Prior to our discussions about STR, both you and Rod probably thought making biofuels was stupid. There are better things one can do with corn than to make ethanol. To use just the kernels of the whole corn plant to enable burning an inferior fuel in gasoline engines is a terrible waste when people are going hungry. Why not make use of the remainder — the corn stalks, cobs, leaves, silk, etc. — instead? That’s what STR/CFO does, and once we’ve had a reasonable discussion about this possibility, both you and Rod seem to feel that maybe biofuels are not so bad. Have you lost? Have I lost? History shows peace generally allows both sides to win. Losers result only when one side, e.g., Rome in its Punic wars, insists on total victory, with Carthaginians not killed being sold into slavery after their city had been razed to the ground.
The links in this are going to send it to moderation. I hope I either get the notice to rescue it, or Rod handles it promptly.
I wrote about corn stover as an energy resource in 2006 and thought it important enough that I re-hosted a corn stover collection project paper to keep it available to the public.
Energy-negative or environmentally damaging biofuels ARE stupid. Using byproducts which have to be processed or destroyed to control pests or just to get them out of the way (like waste fat, corn cobs and excess stover, rice straw and the remnants of cotton plants) makes a great deal of sense. Turning old-growth forest into pulpwood or energy plantation does not. This means there is a rather firm ceiling on the amount of biofuels that aren’t, in your terminology, stupid. That ceiling is also quite low compared to our current consumption. The Green vision of a biofuel economy, given the inevitable denuding of the landscape which would precede its ultimate collapse, is ecocidal. That is so far beyond stupid that the word is inadequate.
Preaching to the choir is not war.
Greens insisting that nuclear power must be eliminated to make room for “renewables” (which are actually about 70% natural gas) are making war. Advocates of nuclear power, like the Breakthrough Institute and Mothers for Nuclear, are just beginning to fight back. There is no money in the defense of nuclear power so the lobbying is still very one-sided, but at least the pushback has begun.
Sorry for the delay
I was wondering what had become of you.
I have been reading your Blog for a few year’s now and truly enjoy the articles and most of the informative comments that I read. I have over 35 years experience in radiation protection and as yourself got my start in the NNPP. I used to blog but generally do not anymore as I have found that there are too many out there who have preconceived ideas based on poor information and in general totally based in opinion versus fact. These people use these blogs as a pulpit to spew ideological views and despise constructive conversation. POA you are one of these people I have read your comments since you first joined the thread and at times you comment rationally and intelligently. I can understand your frustrations with Brian’s and EP’s Acerbic tone (particularly Brian’s) but you regularly attack others without provocation and then try to dial it back later by making replies such as “Thanks for your informative and civil reply” I am an old Irishman who doesn’t mind a dust up now and again but I have learned over the year’s that it is not worth it to try to talk to a singularly minded individual. Unlike your threat to no longer respond to others here you can take mine to the bank. You may opine all you like to my statements but shall not receive a response. The pulpit is yours!
Rod, thank you again for the fine work you do and the service you provide. I will continue to be a visitor here. In case you are wondering I do stay involved in the interests of proper education of the public as it relates to radiation exposure I just choose no longer to do it in these types of forums. I wish you all the best.
Ed Leaver + Rod Adams I should also have mentioned that winds over the oceans experience less friction with the interface because the ocean surface has less topography than the land on continents. Thus, wind at the hub level of the blades is considerably stronger off-shore than on-shore. If you examine wind circulations patterns at the bottom of the troposphere at mid-latitudes, you will see that the wind blows mostly from west to east (because of so-called Coriolis forces on an Earth that spins from west to east) until the winds meet the largely north-south coastlines of the major continents. When the winds meet coastal mountain ranges, some of it turns north-south, and this turning blunts some of the remaining wind speed over land. To close the circulation, the winds over equatorial oceans then reverse direction and blow from east to west again to be turned by continents on the other side of the world.
The simplified description above does not imply that there is no fraction at the boundary between the air and the ocean. Air sliding over water has an instability, technically called the Kelvin-Helmholtz instability, that leads to water waves. An effective (Ekman) drag results between the air and water that gives rise to ocean currents. Although ocean currents are also influenced by thermal and salinity effects, a large part of their driving comes from the winds in the air above them. Thus, the Kuroshio current in the Pacific brings warm water from the tropics to more northerly regions and is responsible for the relatively mild climates of Japan and Korea. The Gulf stream in the Atlantic has the same beneficent effect on Western Europe. Disrupting their steady flows to tap into a reliable source of “renewable” energy, as some have proposed to do by placing water turbines on the sea floor underneath the currents, represents a dangerous activity, promoted by people with an incomplete understanding of the environmental footprints of various natural resources.
One thing that needs to be taken into consideration with offshore wind is the maintenance and operating costs. You may have a greater capacity factor than onshore installations, still less than 50%, but routine maintenance requirements are harder to maintain since the installations are remote and in some cases are located in harsh environments, i.e. the North Sea. Maintenance costs can sometimes account for over 30% of the planned operating costs for a wind farm. Also factor in the costs for insurance and hazard pay and the logistics associated with replacing major components located in the nacelle including the generator, gearbox or drivetrain. Most cases require barge cranes or helicopters and operating crews for each as well as the maintenance technicians.
It will be interesting to see how the Danes, Germans and other offshore wind players will address these issues especially towards end of life and if they will opt to perform major replacements or just retire in place.
Much easier and cheaper to maintain equipment on land that out at sea.
Here in the Pacific Northwest there is lots of hydropower, mostly controlled by Bonneville Power Administration, BPA. In particular, part of the area is the BPA balancing authority region. BPA uses the hydropower resources to keep the voltage and frequency within limits, etc. Most of the wind generators in the region are within the BPA balancing authority area. BPA has made clear that there is a maximum generation from wind farms that BPA can balance. All of those have been built, just over 8 GW nameplate, and no more wind farms are under construction in the Pacific Northwest. Roughly, this represents a maximum of 40% from wind, depending on how matters are measured, and so an achievable average of about 11% from the wind resource.
I take the NREL study with a very large grain of salt. Nobody can manage to control such a large region as the Eastern Interconnect as well as their study suggests.
I think that wind and solar need a major change in technilogy to make them more useful.
1. Big farms concept has to be given up in favour of smaller clusters for distributed generation.
2. Intermittent wind energy should be collected at a lower cost as compressed air. The tall towers could be modified for storage as compressed air. It could even be used directly for mechanical work including water pumping. It is the best medium for climate control via heat pumping. The choice for conversion to electric power remains open at a lower cost and smaller scale.
3. Only a limited spectrum of sunlight is converted to electrical power. The rest can be stored a thermal energy and ued by thermo electric processes and used when photoelectric power is not available.
You need to pick up your calculator. The energy capacity of air even in very tall towers is minuscule, and the conversion losses considerable.
CAES itself is barely viable. There is one going operation in the USA, others that have have been on-again, off-again until finally cancelled, and the Iowa Stored Energy Park test was abandoned.
I think that is opposition for the sake of opposition.
Electrical generation costs are high and compressed atr generation is lower cost.
By normal engineering practice, an optimum pressure for storage, balancing volume and strength will be adopted.
Most of compressed air will be used as such for mechanical work, water pumping and air conditioning using heat pumping at lower cost.
Larger size of tower, wil provide a lot of sunny area for photovoltaic panels and the electricity so stored wil cover essential requirement of electronics and lighting at a standardised 12V saving the costs of conversion.
Please give it a deeper thought.
YOU give it deeper thought, starting with putting numbers to your notions. They are not original (I had the tower-as-air-tank idea long before you did) and learned why there was no stampede toward them when I dug into the details.
Do your own homework. I don’t do it for you.
“I think that is opposition for the sake of opposition.”
Welcome to the comment section of Atomic Insights. Don’t sing off key here, or a small few of the choir members will get kinda in your face about it.
It’s not “opposition for sake of opposition” when someone points out that generalizations that may initially sound great need to be quantified.
Once you begin running numbers using reasonable engineering assumptions, you often discover why a great, original-seeming solution turns out to be inferior to existing practice. I’m not saying that there aren’t still undiscovered ideas out there, but there have been plenty of creative people working on energy solutions for many hundreds of years.
Don’t be surprised or offended if you run into someone who asks for your numbers and equations or if someone who has already taken a similar path dismisses your notions as unworkable or uneconomic.
If the suggested changes in technology are made use of, it will reduce demands of balancing on rest of the system. It will also reduce transmission loads
There are many uses for the unreliables that can be implemented and effectively reduce demand on base load power without the need of storage of the power.
From the mid 1800’s till the mid 1900’s wind power was used on most farms for pumping water for livestock and household use. This was achieved by storing the pumped water. Our farmhouse had a tank in the attic, the cattle had water troughs. The troughs were sized to insure the intermittency of the wind was compensated by the capacity of the trough. Excess, went to the creek that was nearby. Still, I had to check these troughs several times a week till I left for college.
Today that same principle could be used for non time critical applications. The ones that come to mind are sewage treatment plants, water treatment plants, pumped storage power reservoirs, irrigation, even water supply system like the one pumping water from the Colorado river to Los Angeles. There are many others and most could withstand the lack of power for hours and those that could not could withstand the switchover to “grid” power. In fact, the establishment of a second “intermittent” grade power grid should be considered and offered at a rate that would make its use profitable for both suppliers and users.
I’d really like to agree with you Rich. I really wish energy storage really were too cheap to matter.
But it isn’t. Energy storage is a valuable and costly commodity. Otherwise CPUC wouldn’t be scrapping DC so they can deepen their duck pond and fill Hetch-Hetchy with wind.
Rather than build a new PHES system specific to the purpose.
Where? At what cost? Any purpose you can think for energy storage, reliable generation be it coal, gas, or nuclear, can do the same job on one-quarter to one-tenth the amount of storage as solar+wind.
It’s really sobering. You’re the farm kid, so I’ll defer on the matter of irrigation. Some irrigation water storage is right in the ground where it is needed. Perhaps that storage really is cheap.
Water treatment though, perhaps just a few hours. Sewage — just how much raw sewage do you really want to store? Wind and sun routinely go AWOL for days. What do you do for power when it does? Do you have enough storage at your treatment plants to tide you over a week?
No? Then gas. We’re back to co-generation with “natural” gas. Gas is not “backup”. For wind and sun, gas is required co-generation, kW for kW on a capacity basis. Double or triple that per kWh.
I hope you have seen the Colorado River Aqueduct. It is truly impressive. Perhaps poa can fill us in on the reservoir sizes at the high points. I’m not a CE and don’t know what it would take to expand them, or the co-requisite pump capacity, or if the aqueduct even has the reserve capacity to waste on such friviolity.
IIRC the aqueduct is powered by reliable hydro from Parker Dam, where it also siphons it’s water. But if the aqueduct currently runs at max capacity 24/7, then even cutting back to a half-duty cycle will require doubling the earliest pump capacity, near-doubling the first reservoir capacity, and doubling the electric draw from the generators. Perhaps they already have some surge capacity so as to draw more of their power at night. But what will be the cost of adding more? If the water is there, why not use it to pump more water?
Heh. Okay, so more water isn’t there. But as a one-time LA resident, I sure wouldn’t want to see what is to go missing. Ever.
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